Haptic technology is a tactile-feedback technology that, in response to user inputs at a haptic device, applies forces to the user or otherwise controls the user's interaction with the device. The applied forces may be used, for example, to assist in the creation and control of virtual objects. General-purpose haptic devices are commonly used as an assistive technology to enhance a human's interaction within a virtual environment. Applications of haptic devices within virtual environments include, but are not limited to, video games, training surgical procedures, training sports techniques, or physical rehabilitation. Haptic devices commonly take the form of a robot, in which case the point at which a human interacts with such haptic devices may be referred to as the point of physical human-robot interaction (pHRI).
In designing haptic devices, the safety of the human user must be considered, especially at the point of pHRI. To minimize safety concerns, haptic devices today are commonly limited in size. Additionally, haptic devices today commonly utilize software-based safety mechanisms to control large inertia and energetic mechanical components.
As the field of haptic devices continues to evolve, the size of pHRI environments continue to grow. Large pHRI environments may include, as one example, physical rehabilitation environments that are commonly used by users who are weak, disabled, or have a hard time coordinating their limbs. Large pHRI environments may also include, as another example, video-game environments that are commonly used by users that are highly physical and strong, and that therefore may push the limits of haptic devices. Other examples of large pHRI environments may exist as well, with more examples coming into existence every day as haptic technology is increasingly incorporated into various applications.
However, as the size of pHRI environments continue to grow, so too does the size of haptic-device components at the point of pHRI. Such components are increasingly larger and/or are capable of moving with greater forces at the point of pHRI. Accordingly, it has become increasingly difficult to ensure the safety of such pHRI environments at least because such pHRI environments involve components that are capable of moving with relatively high energy and intertia. Such high-energy and high-intertia components may exhibit undesirable forces at the point of pHRI which may at best degrade the user's experience, and may at worst present safety concerns
In particular, it has become increasingly difficult to control large pHRI environments having energetic or high-inertial components with software-based safety mechanisms alone. This is at least because software-based safety mechanisms generally involve active control of components at the point of pHRI. Such active control commonly involves use of electro-mechanical components that, if controlled incorrectly, may pose safety concerns of their own at the point of pHRI. Therefore, there is increasing interest in the development of more effective systems and methods for removing undesirable forces at the point of pHRI, and thereby improving safety and user-experience.